pH-sensitive micelles for targeted drug delivery prepared using a novel membrane contactor method

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Poly(ethylene glycol)-b-polycaprolactone) (PEG-PCL) copolymers are amphiphilic block copolymers used in drug delivery.
• Controlling micelle size and drug loading is crucial for effective nanomedicine formulations.
• Membrane-based methods offer precise control over nanoparticle formation.

Purpose of the Study:

• To develop and characterize a novel membrane contactor method for producing size-controlled PEG-PCL micelles.
• To investigate the influence of process parameters on micelle size and drug encapsulation.
• To evaluate the pH-sensitive drug release characteristics of the prepared micelles.

Main Methods:

• Utilized a microengineered nickel membrane with a hexagonal pore array for micelle production.
• Controlled micelle size by adjusting membrane pore size, transmembrane flux, and agitation rate.
• Encapsulated hydrophobic vitamin E within PEG-PCL micelles and determined encapsulation efficiency and drug loading via ultracentrifugation.
• Assessed drug release profiles at different pH values.

Main Results:

• Micelle size linearly increased with membrane pore size (92 nm for 5 μm to 165 nm for 40 μm).
• Achieved high encapsulation efficiency (89%) and drug loading (~75% w/w) for vitamin E.
• Drug-loaded micelles exhibited a mean size of 146 ± 7 nm with a low polydispersity index (0.09 ± 0.01).
• Demonstrated pH-sensitive release of vitamin E, with maximum release (23%) at pH 1.9.

Conclusions:

• The membrane contactor method provides precise control over PEG-PCL micelle size.
• The developed micelles are suitable for efficient encapsulation and pH-sensitive delivery of hydrophobic drugs.
• Incorporating pH-sensitive bonds did not significantly alter micelle size under tested conditions.